if a Japanese customer asks you to use Malaysian wheels, you must ask the Japanese to buy the wheels, and you should not pay any fees for the wheels, otherwise you can't accept this kind of business, because it is possible that the Japanese and Malaysians may cheat in partnership.

if the Japanese agree to pay for the wheels, you can apply for the processing manual when importing, and you can import the wheels duty-free. After the whole vehicle is exported, you can write off the processing manual.

one more question, do you have import and export rights? If you don't have the right to import and export, you can't complete the business alone. You must also find a foreign trade company to act as an agent for the processing contract. As a result, the cost will increase, and I'm afraid the business will be difficult to succeed.